Inverse dynamics with no external reaction forces

micheal Sacharin · Post by **micheal Sacharin** » Wed Sep 18, 2019 1:56 am

Hello, I made a simple example using the arm26 model and after running a IK simulation of a bending arm, I wanted to check the muscle effort involved in it, just due to the gravity (so without any external reaction forces) so I run a ID simulation with no external forces file selected. In the plotting (moments vs angles) I should see some moments on joints, correct?

Thomas Uchida · Post by **Thomas Uchida** » Wed Sep 18, 2019 7:29 am

I wanted to check the muscle effort involved in it, just due to the gravity (so without any external reaction forces) so I run a ID simulation

ID doesn't compute muscle forces; you should run Static Optimization or CMC.

micheal Sacharin · Post by **micheal Sacharin** » Fri Sep 20, 2019 2:23 am

Sorry, you are right obviously. ID will be able to calculate joint moments even if there are no reaction forces?

Thomas Uchida · Post by **Thomas Uchida** » Fri Sep 20, 2019 6:20 am

The Inverse Dynamics Tool computes the net joint forces/moments that are required to produce the motion you provide. Please see the documentation here: https://simtk-confluence.stanford.edu/d ... e+Dynamics. You may also want to run through Tutorial 3 - Scaling, Inverse Kinematics, and Inverse Dynamics (https://simtk-confluence.stanford.edu/d ... e+Dynamics) if you haven't already.

micheal Sacharin · Post by **micheal Sacharin** » Sat Sep 21, 2019 4:23 am

thanks

Inverse dynamics with no external reaction forces

Inverse dynamics with no external reaction forces

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